Estudo de viabilidade técnica da implantação de pavimentos permeáveis do tipo infiltração total para redução do escoamento superficial, na cidade de Alegrete/RS

Abstract

The growth of impermeable surfaces in cities increases runoff and reduces the infiltration of the soil. An alternative to returning the pre- urban conditions for the use of the soil is permeable pavements. The objective of this work was to verify the possibility of deployment of permeable pavements infiltrative overall in the city of Alegrete/RS, in order to reduce the runoff generated by rainfall. The experiment was conducted in an area located at the Federal University of Pampa/Campus Alegrete. Tests were carried out in this area of infiltration of water in soil and particle size analysis. Three different types of surfaces that can be used to reduce runoff generated by rainfall: permeable concrete blocks, concrete and grass. On each surface were simulated maximum rainfall, calculated according to the IDF curve for Alegrete/RS. The values for the constants of the respective equation, were obtained Pruski et al. (2006). We used a return period (Tr) of 10 years and duration of the precipitation of 10 minutes. For the application of these precipitation has built a rainfall simulator. During the simulations of rainfall were recorded values that rushed over the area of 1m² and end time values were recorded during this period that leaked. Thus it was possible, through the rational method of determining the flow coefficient for each area studied. The results were submitted to analysis of variance and means were compared by Student's t test at the 5% level of probability. The results demonstrate that the waterproofing of concrete and asphalt in cities increases runoff, usually causing urban flooding. The permeable concrete blocks reduce runoff compared with concrete, proving its effectiveness, emerging as alternative impervious surfaces. The grassy surface showed the best results generating little runoff, proving that their removal is detrimental to control runoff. For the city of Alegrete/RS, although the infiltration rate is less than indicated for deployment of permeable pavements infiltrative total, the use of these surfaces is recommended, since it reduced the flow in twenty times, as compared to surfaces concrete. It is also recommended the use of grassed surfaces to reduce the rain runoff.